Merge "Spatializer: add getter/listener for head tracker availability" into tm-dev am: 1a89ec70 am: 14f26cc3

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17211830

Change-Id: I1141ab64c1763eb793b1f6c26ea0da396437984c